Bridge cranes are for instance erected on ocean going ships. The crane is as a rule employed for loading and unloading containers, bulk goods and timber. For more rapid unloading of ships it is frequent practice to employ at least two such bridge cranes.
A number of forms of such cranes have been proposed. Lateral parts are pivoted on two transverse bearers for selective extension of the track so that they are able to be swung out from the position in line with the transverse bearers through 180.degree. into an inactive position in which they are folded back against the transverse bearers on the outside and extend in parallelism to the transverse bearers. This however leads to the disadvantage that no goods may be loaded in the way of the swinging lateral parts and adjacent to the bridge crane. This is especially a disadvantage in the case of container freighters. For the optimum use of the cargo space a plurality of layers of containers must be loaded, it normally is desirable for the pivotal path of the lateral parts to be used as well. This means in practice that aboard container ships conventional bridge cranes are only able to be utilized, after the layers of containers placed adjacent to the bridge cranes have been removed with external load cranes.